THE HISTOLOGY OF THE BLOOD OF LARVA OF LEPIDOSIREN PARADOXA. 293 
concentrically ; and though they seem for the most part parallel, there is a considerable 
amount of apparent crossing and recrossing. 
In profile views (Pl. I. fig. 2 and Pl. IV. fig. 33) there is to be observed at each 
end of the corpuscle an area free of reticular formation, but occupied by a number of 
fine points arranged generally in a straight line. These I take to be the cross sections 
of what appear to be fibrillze seen on the flat. 
Such a peripheral ring has been described in the red blood corpuscles of the chick 
embryo by DrxuEr,* and in amphibian corpuscles by Nicotast and Meves.{ The latter 
has demonstrated that in Salamandra the ring is fibrillar, consisting of very fine threads 
running parallel to one another, or a single unbroken thread developed into a skein in 
the wall of the corpuscle. This is displaced inwards at the beginning of mitosis, under- 
goes a loosening, and then disappears as such, its substance being apparently employed 
for the formation of the achromatic figure. 
The structure thus described by Mrvss is evidently of exactly the same nature as 
the band in the Lepidosiren corpuscles, but he finds no network such as [ have described, 
and the question here arises whether that structure is not a precipitation product. 
A reticular or meshwork structure has been described in amphibian erythrocytes by a 
number of authors (Leypic, Frommann, AvERBACH, Fod, and others), but it has been 
variously interpreted. Gicii0-Tos§ figures a reticulum identically lke that I have 
described, in the erythrocytes of the lamprey. What I have named the microsomes he 
ealls heemoglobigenic granules. Recently RuzicKa || has represented the corpuscles of 
Rana as having a reticular structure closely resembling that seen in the Lepidosiren 
cells. Btrscuui, on the other hand, attributes to the outer portion of the corpuscles 
im Rana an alveolar structure bounded by a distinct membrane. Within this outer 
zone is an inner girdle-like zone of finely meshed internal protoplasm, while the central 
nuclear portion is occupied by a space containing stuctureless enchylema, in which 
there are radiating tracts of protoplasm. 
I do not propose to discuss the history of opinion on the structure of the red discs, 
but [ may mention that Rotterr** in a recent paper concludes for an alveolar stroma, 
while WeIDENREICH’s tt recent observations support ScHAFER’s conclusions (published 
in Quain’s Anatomy), that the contents are fluid and structureless, enclosed by a 
membrane. In this case I feel no doubt of the existence of a membrane, but reserve 
is necessary as to the reticulum. It must be noted, however, that I am dealing with 
young corpuscles. {f 
* Archiv f. mikr. Anat., Bd. 46, 1895. + Babliographre anatomique, 1896. 
t Anat. Anzeiger, Bd. 23, 1903. § Giexi0-Tos, Mem. Accad. delle Sc. Torino, T. xlvi., 1896. 
|| Anat. Anzeiger, July 1903, Bd. 23. ‘| Protoplasm, etc., English trans., 1894, p. 125. 
** Pfliiger’s Archiv f. Physiologie, Bd. 82, 1900. tt Arch. f. mkr. Anat., Bd. 61, 1902, p. 459. 
{{ Mevns, in a paper published since this paper was written (Anat. Anzeiger, vol. xxiv. No, 18), holds that there 
is No membrane in the amphibian corpuscles. The peripheral ring of fibrille is the only structural arrangement in 
Salamandra, but he states that in Rana there is, in addition, a ‘Fadenwerk, which is collected further round the 
nucleus, especially at its poles, and he quotes HensEn (Zeitschr. f. wiss. Zool., Bd. 11, 1862) as having described in the 
corpuscles of the Frog a granular material round the nucleus, from which threads pass to the periphery. 
